The production of liquids, such as liquid oxygen, by the cryogenic rectification of feed air requires the provision of a significant amount of refrigeration to drive the separation because a significant amount of refrigeration is removed from the columns with the product liquid. Generally such refrigeration is provided by the turboexpansion of a process stream, such as a portion of the feed air. While this conventional practice is effective, it is limiting because an increase in the amount of refrigeration inherently affects the operation of the overall process. It is therefor desirable to have a cryogenic air separation process which can produce significant amounts of liquid product wherein the provision of the requisite refrigeration is independent of the flow of process streams for the system.
One method for providing refrigeration for a cryogenic air separation system which is independent of the flow of internal system process streams is to provide the requisite refrigeration in the form of exogenous cryogenic liquid brought into the system. Unfortunately such a procedure is very costly.
Accordingly it is an object of this invention to provide an improved cryogenic air separation process which can produce significant amounts of liquid product wherein the provision of the requisite refrigeration for the separation is independent of the flow of process streams.
It is another object of this invention to provide a cryogenic air separation process which can produce significant amounts of liquid product wherein the provision of the requisite refrigeration for the separation is independently and efficiently provided to the system.